When will the migration boom ease?

Migration has hit a fresh high, with 67,391 long term arrivals in the year to February.

An economist says there is likely to be no let-up in the migration boom until Australia's economy improves.

Migration has hit a fresh high, with 67,391 long term arrivals in the year to February 29. Around 125,000 people arrived and 60,000 left.

Infometrics economist Gareth Kiernan says annual migration is on target to top 71,000 by the middle of the year.

Around 43,000 of those arrivals settled in Auckland, meaning an extra 14,000 houses that are needed in the region.

Migration is being driven by three factors: students, people arriving on work visas and New Zealanders returning home to live.

Net arrivals from Australia for the three months to February hit a 25 year high of 1,606.

Mr Kiernan told Radio Live's James Coleman "One of the keys to trying to judge when that peak might come is when the Australian economy starts to improve and their labour market starts to tighten up a little bit. We have seen a few signs of that over the last six months or so, but still there are fewer people leaving for Australia and more people coming back here."

He admits the momentum of the inbound migration numbers has surprised economists.

Infometrics says the number of arrivals on student visas is still increasing. But growth in the three months to February (3.5% per annum) was the slowest it has been in almost three years.

People arriving from India on student visas peaked in November last year and has since eased 7.1%. However, in the three months to February, student arrivals from China and the Philippines grew strongly (25% and 38%).

Infometrics says the lift in student numbers has helped push total arrivals from China to a 12-year high, while the net migrant inflow from the Philippines has more than doubled over the last two years to an all-time record level.